The speed of the large fish after eating the small fish is 4.76 m/s.
We can apply the law of momentum conservation to calculate the speed of the large fish.
Let the velocity of the large fish after eating small fish is v.
According to law of momentum conservation
m1u1+m2u2=(m1+m2)v
here, m1 is the mass of the large fish, u1 is the initial speed of larger fish, ml is the mass of the small fish, u2 is the initial speed of small fish
10*5+0.5*0=(10+0.5)v
v=4.76 m/s
